A brief history ...

The Plunket Shield started in 1906 and was presented by the then governor-general, Lord Plunket, and was played on a challenge basis between then and 1920-21 (and usually won by either Canterbury or Auckland) since which time it has been a league. The original four teams - Auckland, Canterbury, Otago and Wellington - were joined by Central Districts in 1950-51 and Northern Districts in 1956-57. The instigation of the Shell Trophy in 1975-76 saw the system revamped.